Sized and anti-static coated synthetic fiber and process of coating



SIZED AND ANTLSTATIC CGATED SYNTHETIC FIBER AND PRSCESS F COATING Remus F. Caroselli, Manviile, R. L, assignor to Owens- Corning Fiberglas Corporation, a corporation of Dela ware No Drawing. Application December 2%, 1951, Serial No. 262,650

9 Claims. (Cl. 117 136) This invention relates to the treatment of fibers and fabrics produced therefrom in a manner to render the fibers and fabrics substantially completely and permanently free of static charges.

Static charges, which appear to develop on practically all types of fibers and fabrics produced therefrom, introduce problems which have been ever-present in the fiber and textile field and necessitate the adoption of various devices and steps to minimize the difficulties which arise as a result thereof. In textiles formed of staple or continuous fibers or both, the static charges on the surfaces of the fibers attract dust and dirt particles and such fabrics become difficult to handle because they tend to cling together or to nearby objects or surfaces. The problem of elimination of static charges exists with practically every type of fiber and especially in synthetic fibers formed of resinous materials, such as nylon (polyamide), Vinyon (polyvinyl chloride) and Saran (polyvinylidene chloride) and the like, the latter members being highly polar in nature.

While the invention described and claimed herein has been developed to overcome the static electrical charges which develop on glass fiber surfaces and fabrics produced therefrom, it has been found that the new anti-static treatment is also applicable as an anti-static treatment for nylon, Saran, Vinyon and other such synthetic fibers wherein the development of static charges have presented a problem in production and use and that the new antistatic treatment is also effective on natural fibers and fabrics produced therefrom.

Overcoming the development of static charges on glass fibers has presented the greatest problem because of the Wholly inert and mineral character of such fibers as compared to the other fibers. Modification of the glass composition of which the fibers are formed very often cannot be tolerated and application of materials to modify the characteristics of glass fibers and fabrics produced therefrom have been most difficult. A number of treatments have been devised for minimizing the development of static charges on such fibers as cotton, wool and silk but such treatments apparently are unapplicable and have little, if any, affect as an anti-static treatment of glass fibers. Fortunately, the anti-static treatment which has now been discovered for glass fibers may be used with marked success with practically all other fibers.

It is an object of this invention to produce fibers and fabrics which are treated to become substantially completely and permanently free of static charges and it is a related object to provide methods for effecting same.

Another object is to produce and to provide a method for producing fibers and especially glass fibers free of static charges, and it is a related object to provide an anti-static treatment for such fibers and fabrics produced therefrom and to render such fibers and fabrics substantially permanentlyfree of static charges.

A large number of compounds, treatments andthe like have been employed in the processing of fibers for the purpose of reducing their tendency for developing static United States Patent 0 charges or for eliminating static charges already existing thereon. Treatments of fibers with some compounds appear to benefit certain types offibers but are wholly in capable of use with others in a manner to develop the desired results and there appears to be no one composition or treatment available to the present which can be used with all of the types of fibers to eliminate static charges. No composition or treatment has been developed to the present which is capable of introducing anti-static characteristics which remain practically as effective after laundering or dry-cleaning as before permanently to eliminate the static problem. These generalizations are particularly true with respect to glass fibers.

It is an object of this invention to produce fibers and fabrics which are treated to become substantially com pletely and permanently free of static charges and it is a related object to provide methods for effecting same.

Another object is to produce and to provide a method for producing glass fibers free of static charges, and it is a related object to provide an anti-static treatment for glass fibers and fabrics produced therefrom and to render such fibers and fabrics substantially permanenty free of static charges.

A large number of compounds, treatments and the like have been employed in the processing of fibers for the purpose of reducing their tendency for developing static charges or for eliminating static charges already existing thereon. Treatments of fibers with some compounds appear to benefit certain types of fibers but are wholly incapable of use with others in a manner to develop the desired results and there appears to be no one composition or treatment available to the present which can be used with all of the types of fibers to eliminate static charges. No composition or treatment has been developed to the present which is'capable of introducing anti-static characteristics which remain practically as effective after laundering or dry-cleaning as before permanently to eliminate the static problem. These generalizations are particularly true with respect to glass fibers. i

It has been found that the much desired anti-static characteristics may be introduced into glass fibers in a manner which is substantially permanent and resists de terioration responsive to washing or dry-cleaning or other- Wise handling in the manner intended when glass fibers or fabrics formed therefrom are treated with a water soluble polysiloxanolate having one or more saturated alkyl, aryl or mixed alkaryl organic groups of relatively short carbon length attached directly to the silicon atom. It has been found further that the organo polysiloxanolate is effective'not only with glass fibers and products produced therefrom but that the anti-static treatment with polysiloxanolate compounds is effective also with other fibers, such as wool, silk, cotton and cellulose, and with synthetic fibers formed of polyamides (nylon), polyvinyl chloride (Vinyon), polyvinylidene chloride (Saran), proteins and other resinous or elastomeric materials.

An organo polysiloxanolate of the type which may be used in the practice of this invention comprises a Water soluble salt of po'lysiloxanol having organic groups attached directly to silicon containing 1 to 8 carbon atoms in straight chain or ring arrangement. Suitable polysiloxanolates may be represented by the general formula in which M is a nonvalent cation, such as sodium, potassrum, ammonium and the like; one or more of the -R groups constitute an alkyl, aryl or alkaryl radical having one or more but not more than 10 carbon atoms and p'refer'ablysaturated' in'their'carbon to carbon linkages, such forexampleas "methyl, ethyl, propyl, butyl, amyl, isoamyl, isobutyl, hexyl, heptyl, benzyl, tolyl, and the like. The remaining R groups are hydrogens or other aliphatic or aromatic organic groups. Z may be an R group of the type described in the event that the poly-- siloxanolate is formed of a silane having the general formula RzSiXz in which X is a replaceable or hydrolyzable halogen, such as chlorine, bromine or the like, or a hydrolyzable ethoxy group of short carbon length.

such as methoxy, ethoxy or the like. Polysiloxanolatcs of the type which may be formed from such silanes are represented by the general formula n I a I Mo-di--(0,si -o-ru i it Instead, Z may be a grouping of the type JY Y I It o -M -"o tii-o ,.-sim; os1-0 M i it i or mixtures thereofin the event that the silane from which the polysiloxanolate is formed has threereplaceable or hydrolyzable groups, such. as RSiXa wherein R and X correspond to the groupings described. Y can be R, as previously identified, -O-M, or -O- to which is'attached another silicon oxide chain or the like. In the event that the polysiloxanolate is formed of a mixture of silanes having two or three hydrolyzable groups, the polysiloxanolate may have R groups substituted for Y in some places to terminate and form smaller, more water soluble compounds. The following structural formula represents a compound of the type formed by a silane having three available hydrolyzable groups:

Representative compounds are sodium amyl polysiloxanolate, sodium ethyl polysiloxanolate, potassium hexyl polysiloxanolate, ammonium isobutyl polysiloxanolate, sodium benzyl polysiloxanolate, and the like.

As in the manufacture of polysiloxanolates by reaction of the corresponding silane or silanes through hydrolyzation to form the silanols, suitable polymeric compounds, such as the preferred low molecular weight materials, may be secured bythe addition of the respective silanes, such as trichloroamyl silane, dichlorodiarnyl silane, diethoxydibutyl silane, dichloroethylamyl silane, or trichlorobutyl silane or the like to an ice cold solution of the alkali metal hydroxide. to form the corresponding alkali metal polysiloxanolate. Enough alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide or ammonium hydroxide should be present to satisfy the free chlorine or other hydrolyzable. groups in forming the corresponding polysiloxanolate. For reaction the solution should contain about 35 percent by weight silane and the pH of the solution ordinarily is maintained at 10-12. Reference is also made to Patent No. 2,567,110 for the preparation of polysiloxanolates.

The nature of the phenomenon or the reaction by which the anti-static properties are developed in glass fibers or other fibers by treatment with the polysiloxanolate is not now capable of explanation. It is known that the glass fibers become substantially free of static charges whether the polysiloxanolate is applied directly to the glass fiber surfaces or incorporated into a size or other treating or protective coating applied to the glass fiber surfaces or applied separately before or after treatment with such other size or protective coating. The organo polysiloxanolate contains groupings which are capable of strong coordination with. the groupings that predominate on the 4 1 glass fiber surfaces so that the polysiloxanolate appears to become a permanent part thereof upon application and insolubilization. The groupings available in the organic radicals of the polysiloxanolate also appear to be highly receptive to groupings that exist in organiesizes and other resinous, proteinaceous, carbohydrate and elastomeric substances with which glass fibers are often sized or coated. As a result, the polysiloxanolate also appears to encourage adhesion or anchorage of these coating and resinous materials to the glass fiber surfaces when treated with the polysiloxanolate or when the polysiloxanolate is incorporated in the size, coating, or treating composition.

Maximum effectiveness as an anti-static treatment appears to result when the polysiloxanolate is applied directly onto bare glass fiber surfaces as by the treatment of glass fibers in forming or by treatment of fibers after the size or other coating has been removed by heat treat meat or washing. While there are some applications where it will be suflicient to apply the anti-static treatment to bare glass fibers, in most instancesa protective coating will also be needed. Unless the polysiloxanolate contains organic groups of sufiiciently long carbon length, the treated fibers will be unable to resist damage or destruction by abrasion. Application of a protective coating, such as a resinous material or the like, does not appear materially to affect the anti-static treatment and, as previously pointed out, it has been found that the anti static treatment is also secured when, instead of separate applications,the polysiloxanolate is embodied as an ingredient in the protective coating composition which makes possible the development of the desirable properties in glass fibers in a single treating step. In the event that a suitable protective coating is already formed on the glass fiber surfaces or on a finished fabric formed therefrom, it has been found suflicient to apply the anti-static polysiloxanolate compound by wash coating the fabric with a solution of the polysiloxanolate in suitable concentration.

It has been found that the treatment to render the polysiloxanolate more permanent on the glass fiber surfaces should include the step of reacting the polysiloxanolate, generally supplied as a strongly alkaline solution having a pH of about 10-12, with an acidulating compound or acidulous aqueous solution followed by the elimination of residual water'soluble salts which may be formed as byrinsing the fibers after the polysiloxanolate has been insolubiiized on the surfaces thereof. The treated fibers may be air dried, but it is preferred to heat the treated fibers at a temperature within the range of 300-350" F. to accelerate the drying and set the polysiloxanolate on the glass fiber surfaces. 7 y

The acidulating medium may be applied asa separate treatment after the polysiloxanolate has been set on the glass fiber surfaces or it may be incorporated as an ingredient in the anti-static treating composition, which may or may not also contain a protective agent for introducing abrasion resistance. When incorporated as an ingredient in combination with the polysiloxanolate, it has been found most desirable to add sufiicient acidulating medium to adjust the pH of the composition to between 5 and 8. Suitable acidifying agents may be selected from mineral acids, such as hydrochloric acid, sulphuric acid, phosphoric acid and sulfamic acid or salts formed of these strong acids and weak bases, such as ferric nitrate, ferric chloride, ammonium monobasic or dibasic phosphate; and the like.

When applied alone or in combination with a resinous material or other protective agent in a treating composition, it will be suflicient if the concentration of the polysiloxanolate in the anti-static treating composition ranges from 0.1 to 2.0 percent by weight. Higher concentrations may be used but such greater amounts are disproportionate to the improvement in anti-static treatment.

This invention in anti-static treatment of glass fibers may be illustrated by the following examples:

.Erample 1 Bare heat cleaned glass: fibers orgglass-fibers in formingrmay be treated by application of. an aqueous composition containing 0.8 percent by weight potassium isobutyl polysiloxanolate. When applied informing, the composition. may be wiped onto the strands by the usual wiping pad or roll, applicator. Application may be made to heat cleaned glass fibers or fabrics by means of a padder or the like or by other conventional coating processes, such as roller coating, dip coating, spray coating or the like. To render the anti-static treatment more permanent, it has been found desirable toheat the treated glass fibers to a temperature within the range of 300-350 F. for 5:30 minutes. After drying, the treated fibers are acidulated with a 5 percent solution of hydrochloric acid applied to the glass fiber surfaces in a similar manner as the polysiloxanolate composition. Application of the acidulating medium is followed by drying and then the dried fibers are preferably rinsed with water to remove any residual salts which might have been formed.

Example 2 Instead of applying the polysiloxanolate and the acidulating medium in separate, solutions, as inEXample 1, treatment may be elfected more economically by combirding the two ingredients in a single composition in an aqueous medium containing 0.4 percent by weight of sodium hexyl polysiloxanolate adjusted to a pH of about 6 by, titration with a mineral acid, such as phosphoric acid, and then drying thetreated fibers at ,a temperature of 320 F. for -15 minutes.

Example 3 Although it is preferred to apply the, composition containing the polysiloxanolate onto the bare glass fiber surfaces, whether in the form of individual fibers, strands,

yarns, or fabrics, marked reduction in the development of static charges can be achieved when the polysiloxanolate is applied onto fibers which already have a protective or coating agent thereon. For example, yarn sized with a composition containing 8 parts by weight dextronized starch, 2 parts by weight hydrogenated oil, /2 part by weight octadecylamine chloride and 0.2 part by weight nonioriic emulsifying agent may be treated without removing the size with a 0.5 percent by weight water solution of sodium amyl polysiloxanolate. The treated fibers are preferably dried at a temperature of about 330 F. for or minutes. Acidulation of the treated fibers may be carried out with a 3-6 percent solution of ferric chloride or the acid salt may be incorporated directly into the polysiloxanolate composition in an amount to adjust the pH to between 5 and 8. Sheer marquisette having a static charge of 60 volts before treatment is cut down to a charge of only 3 volts by treatment in the manner described.

Example 4 In a preferred treatment of glass fibers when arranged in textile form, the glass fibers, after heat cleaning, are treated with a composition containing 10 percent by volume of a polyacrylate dispersed in about percent by weight aqueous medium (Hycar PA, marketed by the B. F. Goodrich Chemical Company) and 10 percent by volume of a 4 percent solution of sodium amyl polysiloxanolate (SS-5 manufactured by Cowles Chemical Company) and 80 percent by volume Water. The aqueous composition is applied onto the clean fabric by conventional means, such as a padder, and the treated fabric is heated at a temperature of 320-340 F. for about 10-30 minutes. Although the mechanism of the reaction or the phenomena developed are not understood, it appears that the temperature of drying in this specific type of combination is quite critical because upon drying at temperatures outside the range of 300-350 F., permanent anti-static characteristics are not developed.

After the coating has dried the fabric is acidulated witha 4 percent solution of hydrochloricacid and the dried fabric is further rinsed in ,water to remove any residual salts which might be developed. If the treated fibers are vigorously agitated during or after acidulation, the. continuity of the resinous film on the glass fiber surfaces will. be broken and the fiber will, as a result, be more. relaxed and have a softer and better feel.

.A. fabric; treated in the manner described is characterized by substantially permanent anti-static properties and it also possesses a surface which. is highly receptive to resonous. or other. treating, materials thereby to enhance the bonding relation of such materials with the glass fiber surfaces. Treatment in the manner described introduces little, if any, discoloration in the glass. fiber fabric which is an important characteristic when such fabrics are used as textiles in. the manufacture of dress goods, draperies, or the like.

Example 5 The components of Example 4 may be applied in separate treatments in which 10 percent by volume of the polyacrylate resin (Hycar PA) in water dispersion is applied first onto heat cleaned fabrics or glass fibers by conventional means and the polysiloxanolate solution applied afterwards, preferably with the acidulating sub stance combined therewith in an amount to reduce the pH to about 6.5. When the polysiloxanolate is applied separate and apart from the polyacrylate composition, greater concentrations thereof in the treating solution have been found desirable. In many cases the concentration. of polysiloxanolate is doubled. over and above that used in. cornbinationwith the resinous material, when applied separately.

Example 6' 10. percent by volume Hycar PA (50 percent dispersion of polyacrylate in water) 10 percent by volume sodium amyl polysiloxanolate (4 percent solution in water) 1 percent by Weight ammonium sulfamate percent by volume water The above formulation for a treating composition em bodies all of the. elements of a protective agent, antistatic agent and an acidulating substance therefor. The composition is adapted to be applied. onto. sized or prefer ably heat cleaned glass, fiber fabric by means of a padder or other conventional coating system and the treated fabric is dried at a temperature of about BOO-350 F. for 15-20 minutes. When dry, the fabric is rinsed with Water to remove residual water soluble salts which may beformed.

Instead of the polyacrylate which is preferred in the application of a protective coating onto glass fiber surfaces, especially when the glass fibers are to be used as a base for coated fabrics or as a reinforcement in plastics, a large number of other preferably film forming resinous coatings and impregnating materials might be used separate and apart from or in combination with the. polysiloxanolate in glass fiber treatment. Representative of such; other resinous materials, are polyvinyl acetate, butadiene-styi'ene copolynier, polystyrene, polyethylene, polybutylene, cellulose ethers and esters and the like, starches, proteins, sugars and other ingredients used in glass fiber sizes such as phenol formaldehyde resin, urea formaldehyde resin, furfuryl alcohol resins, and the like used as bonding agents for glass fibers in the manufac ture of bonded mat and fabrics. The amount of resinous material in the treating composition depends largely upon the type of treatment and use to be made of the fiber or fabric. Usually the amount which can advantageously be used in combination with the polysiloxanolate in the treating composition varies from 225 percent by weight.

a r I 7 Example 7 The treatment of synthetic resinous fibers in the mannot described to reduce the static charges developed thereon is not quite as startling as with glass fibers. With such synthetic fibers or natural fibers, protection to prevent destruction by mutual or other abrasion is not necessary and anchorage is achieved by means of absorption, as a result the polysiloxanolate can and preferably is applied alone or in combination with the acidulating medium, such as described in Examples 1 and 2.

Nylon fiber may be treated with a 0.5 percent solution of sodium amyl polysiloxanolate adjusted with phosphoric acid to a pH of about 6. The fiber is dried at elevated temperatures and then rinsed with water to remove soluble salts. The natural nylon fiber gives a static charge of 50 volts while the static charge on the treated fiber is cut down to 15 volts and this reduction remains substantially consistent even after normal handling and wear. Corresponding amounts such as 0.5 to 1 percent by weight sodium amyl polysiloxanolate or the like may be applied to other synthetic fibers such as Saran, Vinyon, soya portein fibers and the like followed by drying at elevated temperature and rinsing in water to remove salts. Such fibers also exhibit marked improvement in resistance to the development of anti-static charges thereon. As previously pointed out, treatment in the manner described to reduce the development of static charges may also be applied in similar concentrations to natural fibers such as cotton, wool, silk, hemp, flax and the like.

The anti-static treatment of glass fibers and all other fibers described and claimed herein makes available for the first time means for substantially completely and permanently eliminating static charges in all types of fibers. Various modifications to incorporate the polysiloxanolate are possible and from every test which has been made such association of a saturated polysiloxanolate appears favorably to affect the anti-static properties especially when applied directly onto the fiber surfaces and set thereon by heat and by acidulating substance. It is not known whether the heat for drying is necessary in all instances to impart greater permanence in the developed anti-static characteristics but it is known that greater permanence results upon heating to temperatures within the range of BOO-350 F. when the polysiloxanolate is applied in combination with a polyacrylate or other resinous protective coating or material.

It will be apparent that a number of changes may be made in the formulations and in the steps for application and treatment of the polysiloxanolate treating composition without departing from the spirit of the invention, especially as defined in the following claims.

I claim:

I. Glass fibers and fabrics formed thereof coated with a glass fiber size and an anti-static material in the form of a water soluble polysiloxanolate insolubilized on the surfaces thereof and in which the organic radicals attached directly to silicon are saturated and contain 1-10 carbon atoms.

2. In the anti-static treatment of glass fibers and fabrics formed thereof, the steps of treating the glass fibers with an aqueous composition adjusted by an acidic substance to a pH. of 58 and containing from 0.1 to 2.0 percent by weight of a water soluble polysiloxanolate in which the organic radicals attached directly to silicon are saturated and contain l-l0 carbon atoms, drying the treated fibers at. elevated temperature, rinsing the fibers with water to remove soluble salts, and treating the anti-static treated fibers with a glass fiber size composition containing a film forming material.

3. in the anti-static treatment of glass fibers and fabrics formed thereof, the steps of coating the glass fiber surfaces with a glass fiber size composition containing a film forming material, treating the sized fibers with an aqueous solution containing 0.1 to 2.0-percent by weight of a water soluble polysiloxanolate in which the organic radicals attached directly to silicon are saturated and contain 1-10- carbon atoms, treating the coated fibers with an acidulous aqueous medium, and then rinsing the fibers with water after drying to remove soluble salts.

4. In the anti-static treatment of glass fibers and fabrics formed thereof, the steps of treating the glass fibers with a size composition, applying onto the sized fibers an aqueous solution adjusted to a pH between 5 and 8 with an acidulating substance and containing 0.1 to 2.0 percent byweight of a water soluble polysiloxanolate in which the organic radicals attached directly to silicon are saturated and contain l-10 carbon atoms.

5. In the anti-static treatment of glass fibers and fabrics formed thereof, the steps of coating the fibers with an aqueous composition containing a film forming material for sizing the glass fibers, and containing in addition to the film forming material, 0.1 to 2.0 percent by weight of a water soluble polysiloxanolate in which the organic radicals attached directly to silicon are saturated and contain ll0 carbon atoms, and an acidulating substance to reduce the composition to a pH between 5 and 8, heating the coated fibers to a temperature within the range of 300*3 50 F. and then rinsing the fibers in water to remove soluble salts.

6. In the anti-static treatment of glass fibers and fabrics formed thereof, the steps of coating the fibers with an aqueous composition containing afilm forming material capable of being set upon the glass fiber surfaces upon drying and containing in addition to the film forming material 0.1 to 2.0 percent by weight of a water soluble polysiloxanolate in which the organic radicals attached directly to the silicon atom contain less than 10 carbon atoms and are saturated, heating the coated fibers at a temperature within the range of 300350 F., washing the coated fibers with an acidulous aqueousmedium, and then rinsing the fibers with water to remove soluble salts which might be formed.

7. The method as claimed in claim 4 in which the treated fibers are washed in aqueous medium with vigorous agitation to break up the continuity of the size coating.

8. In the anti-static treatment of synthetic fibers and fabrics formed thereof, the steps of sizing the fibers with an aqueous composition containing a filrnforming material for sizing the fibers and containing in addition to the film forming material 0.1 to 2.0 percent by weight of a water soluble polysiloxanolate in which the organic radicals attached directly to the silicon atoms are saturated and contain from 1-10 carbon atoms.

9. Synthetic fibers and fabrics formed thereof in which the fibers are sized with a film forming material and a water soluble polysiloxanolate which is insolubilized on the surfaces thereof in addition to the film forming material to impart anti-static properties to the fibers and in which the organic radicals attached directly to the silicon atom of the .polysiloxanolate are saturated and contain from l-l0 carbon atoms.

References Cited in the file of this patent UNITED STATES PATENTS 2,354,110 Ford et a1 July 18, 1944 2,392,805 Biefield Jan. 15,1946 2,492,498 Pedersen Dec. 22, 1949 2,507,200 Elliott et al. May 9, 1950 2,587,636 MacMullen Mar. 4, 1952 2,630,620 Rand Mar. 10, 1953 2,635,060 Cheronis et al. Apr. 14, 1953 

8. IN THE ANTI-STATIC TREATMENT OF SYNTHETIC FIBERS AND FABRICS FORMED THEREOF, THE STEPS OF SIZING THE FIBERS WITH AN AQUEOUS COMPOSITION CONTAINING A FILM FORMING MATERIAL FOR SIZING THE FIBERS AND CONTAINING IN ADDITION TO THE FILM FORMING MATERIAL 0.1 TO 2.0 PERCENT BY WEIGHT OF A WATER SOLUBLE POLYSILOXANOLATE IN WHICH THE ORGANIC RADICALS ATTACHED DIRECTLY TO THE SILICON ATOMS ARE SATURATED AND CONTAIN FROM 1-10 CARBON ATOMS. 